6. Positive pregnancy test within 24 hours of study infusion or an unwillingness to undergo pregnancy testing in females of child-bearing potential. Females capable of child-bearing must agree not to become pregnant from the time of study enrollment until at least 28 days after completion of study treatment period. If a woman is sexually active and has no history of hysterectomy or tubal ligation, she must agree to use 2 acceptable contraceptives (see section 7.4.1.) while participating in the study and for 28 days following the last dose of study drug.